Dean is used to Cas following him, like an awkward, trenchcoat wearing specter. When he’s honest with himself–and that doesn’t happen often–he’ll admit he likes it.
So the first time he wakes up, and Cas isn’t in his chair next to Dean’s bed, eyes intent on the tiny screen where Netflix plays, he feels a strange pang of loneliness.
Even waiting for the other shoe to drop, he doesn’t like waking to find the angel is gone.
Except he isn’t. Dean goes still in the door of the kitchen, watching the scene with big eyes. Cas, eating cereal and sipping his coffee, hair fucked up and enticing, reading a newspaper while Sam babbles facts from his thick biography.
Cas smirks and shakes his head and Sam pauses, a grin in his voice. “What?”
“That’s not how it happened.”
And then he’s off, correcting the text with what really happened and Sam is staring at him and Dean would bet money that his brother looks starstruck.
Cas notices him as he’s winding down, like he didn’t just casually rock Sam’s world and his expression brightens a little.
“Dean. Would you like some coffee?”
It goes like that, then. Dean will fall asleep with Cas there, and wake to him gone. He’ll wander in to find Sam and Cas quietly discussing what they’re reading over coffee and cereal and gross as fuck oatmeal that Sam insists is healthy, and Cas pours honey and berries into and that still doesn’t make the shit edible.
They trade books in the Impala and Cas struggles to understand fiction for a while but when he does, oh damn, it’s like a whole fucking world opens up. Or worlds. Sam dumps books on him by the bagful and Dean watches with slightly exasperated amusement as his room becomes cluttered with Castiel’s reading material.
He’s migrated from the chair to a pillow propped spot on the bed next to Dean and sometimes, Dean will come to his room to find Cas there, book open in his lap, wearing sleep pants and one of Dean’s old tshirts, Sam sitting at the edge of the bed, voice blurry with sleep as they discuss the finer points of a Lannister’s betrayal.
It happens slowly, as with most things that involve Cas.
But one day, he leans over the bench seat of the Impala, turns down the radio and rests his head on Dean’s shoulder as he reads a page to Sam and then they’re talking and Dean rolls his eyes, full to the brim with exasperated affection for his brother and his angel.
Because Castiel is his, always has been. The slow dance they’re doing around and to each other has an inevitable conclusion but he’s not in any rush, figures Cas needs time to figure out being human and who he is aside from Dean’s.
Apparently that includes being a bibliophile and Sam’s bestie and Dean might give them shit for being geeks, but he doesn’t actually mind. He kinda loves it, loves how easy they are together, that they share something that doesn’t include him.
They need friends, after all, and the two people he loves most should like each other.
Still, he rolls his eyes and mutters, “Geeks.”
It earns a bitch face from Sam and a soft hush from Cas, followed by an absentminded kiss to his cheek before he resumes his conversation.
Sam’s face melts into sappy sweet awestruck and Dean’s breath feels caught in his throat–right up there with his heart which is pounding too hard.
“I think Aslan is God. Though clearly Lewis is wrong about his presence,” Castiel says seriously, and Sam balks because he’s still Sam and has that absurd faith and Dean laughs softly and hums AC/DC under his breath as the two people he loves most argue about literature and the miles slip by.